ceph/src/boost/boost/property_map/function_property_map.hpp

   1 //
   2 //=======================================================================
   3 // Author: Philipp Moeller
   4 //
   5 // Copyright 2012, Philipp Moeller
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See
   8 // accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10 //=======================================================================
  11 //
  12
  13 #ifndef BOOST_PROPERTY_MAP_FUNCTION_PROPERTY_MAP_HPP
  14 #define BOOST_PROPERTY_MAP_FUNCTION_PROPERTY_MAP_HPP
  15
  16 #include <boost/config.hpp>
  17 #include <boost/property_map/property_map.hpp>
  18 #include <boost/type_traits.hpp>
  19 #include <boost/utility/result_of.hpp>
  20 #include <boost/mpl/and.hpp>
  21 #include <boost/mpl/not.hpp>
  22 #include <utility>
  23
  24 namespace boost {
  25
  26 template<typename Func, typename Key, typename Ret = typename boost::result_of<const Func(const Key&)>::type>
  27 class function_property_map: public put_get_helper<Ret, function_property_map<Func, Key, Ret> > {
  28   public:
  29   typedef Key key_type;
  30   typedef Ret reference;
  31   typedef typename boost::remove_cv<typename boost::remove_reference<Ret>::type>::type value_type;
  32
  33   typedef typename boost::mpl::if_<
  34                      boost::mpl::and_<
  35                        boost::is_reference<Ret>,
  36                        boost::mpl::not_<boost::is_const<Ret> >
  37                      >,
  38                      boost::lvalue_property_map_tag,
  39                      boost::readable_property_map_tag>::type
  40     category;
  41
  42   function_property_map(Func f = Func()) : f(f) {}
  43
  44   reference operator[](const Key& k) const {
  45     return f(k);
  46   }
  47
  48   private:
  49   Func f;
  50 };
  51
  52 template<typename Key, typename Func>
  53 function_property_map<Func, Key>
  54 make_function_property_map(const Func& f) {
  55   return function_property_map<Func, Key>(f);
  56 }
  57
  58 template<typename Key, typename Ret, typename Func>
  59 function_property_map<Func, Key, Ret>
  60 make_function_property_map(const Func& f) {
  61   return function_property_map<Func, Key, Ret>(f);
  62 }
  63
  64 } // boost
  65
  66 #endif /* BOOST_PROPERTY_MAP_FUNCTION_PROPERTY_MAP_HPP */